For lighting purposes, instead of gas discharge lamps and incandescent lamps, light emitting diodes are increasingly being used as light source. The efficiency and luminous efficiency of light emitting diodes is being increased to a greater and greater extent, such that they are already used in various applications for general lighting. However, light emitting diodes are spot light sources and emit highly focused light.
Present-day LED lighting system often have the disadvantage, however, that the color emission or the brightness can vary on account of ageing or as a result of replacement of individual LEDs or LED modules. Moreover, the secondary optics influence the thermal management since the heat emission is impeded. Moreover, a variation of the phosphor of the LED can occur on account of ageing and the action of the heat.